In manufacturing process of semiconductor devices such as IC and LSI, fine process by lithography with a photoresist composition has been conventionally carried out. In recent years, ultrafine pattern formation of a sub-micron region and a quarter micron region has been required with higher integration of integrated circuits. In such a circumstance, exposure wavelength also shows a tendency to become shorter such as from a g line to an i line, and further to a KrF excimer laser ray. Further, besides a KrF excimer laser ray, development of lithography using an electron beam, an X-ray or an EUV ray is also now progressing.
Lithography using electron beam, X-ray or EUV ray is positioned as a pattern-forming technique of the next generation or the next of the next generation, and resist compositions of high sensitivity and high resolution are desired.
In particular, for shortening processing time of wafers, increase of sensitivity is a very important subject. However, pursuit of higher sensitization is accompanied by lowering of pattern form and resolution that is represented by limiting resolution line width, accordingly development of a resist composition satisfying these characteristics at the same time is strongly desired.
High sensitivity, high resolution and good pattern form are in a relationship of trade-off, and it is very important how to meet these characteristics at the same time.
There are generally two types of actinic ray-sensitive or radiation-sensitive resin compositions, that is, one is a “positive” resin composition using a resin hardly soluble or insoluble in an alkali developer and capable of forming a pattern by making an exposed part soluble in an alkali developer by exposure with radiation, and another is a “negative” resin composition using a resin soluble in an alkali developer and capable of forming a pattern by making an exposed part hardly soluble or insoluble in an alkali developer by exposure with radiation.
As such actinic ray-sensitive or radiation-sensitive resin compositions suitable for lithographic process using electron beams, X-rays or EUV rays, chemical amplification positive resist compositions primarily utilizing acid catalytic reaction are examined from the viewpoint of the increase in sensitivity, and chemical amplification positive resist composition comprising phenolic resin having a property insoluble or hardly soluble in an alkali developer and capable of being soluble in an alkali developer by the action of an acid (hereinafter abbreviated to a phenolic acid-decomposable resin), and an acid generator as the main components are effectively used.
On the other hand, in manufacturing semiconductor devices and the like, there are requirements to form patterns having various shapes such as lines, trenches, holes, etc. For meeting the requirements for forming patterns having various shapes, not only positive compositions but also negative actinic ray-sensitive or radiation-sensitive resin compositions have also been developed (for example, refer to JP-A-2002-148806 (The term “JP-A” as used herein refers to an “unexamined published Japanese patent application”.) and JP-A-2008-268935).
In forming super fine patterns, further improvements of the reductions of resolution and a pattern form are required.
For solving these problems, a method of developing an acid-decomposable resin with a developer other than an alkali developer is also proposed (for example, refer to JP-A-62-175739, JP-A-2006-227174 and JP-A-2008-292975).
Further, there is known a pattern-forming method to utilize that the main chain of a resin is directly cut by exposure (for example, refer to Japanese Patent No. 3277114).
However, it is the present state of things that high sensitivity, high resolution, a good pattern form and a residual film rate in a super fine processing region are not satisfied at the same time.